THIS mild and wet winter can cause tremendous problems for free-range chickens and Barry Thorp, the Scottish specialist for the St David's Poultry Team, explains in this article how to maximise productivity.

'Cold, sunny and dry weather is ideal for reducing the disease burden on poultry ranges, so it's not surprising that this year's winter has been challenging for free-range producers faced with muddy pasture and wet litter.

That means disease and parasites are in plentiful supply. To overcome this, farmers should aim to maximise their birds' intestinal health.

Most gut problems happen at times of stress - when pullets arrive on farm or reach peak lay, for example. Signs include frothy yellow droppings, reduced feed and water intake, slow weight gain and small eggs with poor shell quality.

To minimise stress, producers should reduce disease challenges through careful terminal cleaning and range management. That may be easier said than done in a season like this.

The key to range management is drainage, as standing water can harbour bacteria that can cause diarrhoea. Producers should use French drains and areas of hard standing around the house, and rotate paddocks to give pasture a break.

Sunlight aids eliminating bacteria, viruses and parasites, so it helps to keep grass short and trees trimmed to maximise the light reaching the soil's surface. It's also worth applying agricultural lime at turnaround to help destroy worm eggs and other pathogens.

The main worms to look out for are ascaridia, capillaria and heterakis. The first two irritate the gut lining, reducing nutrient absorption and causing diarrhoea and, although heterakis are not harmful in their own right, they can carry blackhead, which is potentially fatal to chickens.

We recommend producers take faecal egg counts every 6-8 weeks and use a licensed wormer if required, paying attention to dose rates to reduce the danger of anthelmintic resistance building up.

It's also important to use an approved disinfectant at cleanout, as not all disinfectants will destroy worm eggs.

If you're using borehole water, it's vital to have a water treatment system that is regularly serviced.

Even with mains water bacteria can build up, so use a stabilised hydrogen peroxide-based sanitiser and flush drinker lines weekly.

To bolster the birds' gut health and immunity, producers should consider using feed or water additives at times of stress or throughout lay. Probiotics can be given to increase the population of 'good' bacteria in the intestine and out-compete 'bad' bacteria.

Protected organic acids, which make the gut more acidic, will also encourage the 'good' bacteria, while discouraging harmful bacteria. In addition, they help in the development of villi in the gut, which directly boosts nutrient absorption and improves performance.

Mannan oligosaccharides (natural nutritional supplements) can also be beneficial, binding to the surface of harmful bacteria and preventing them from attaching to the gut.